[Cole_Robbie]

There might not be a lot of environmental impact, but the weakness is still in the leaching out of the fertilizer, even if it only wastes good fertilizer. I'm sorry to be Captain Bringdown, and I do admire your outside-the-box thinking.

What you have (re-)invented is raft hydroponics or raft-style aquaponics, which was likely one of the very first ways that early humans raised food. Early humans were hunter-gatherers, but we are just now figuring out that they did practice agriculture, too. They would plant when they were in one area and then come back at a later date and eat from those crops as they passed through. It is theorized that raft aquaponics may have been the first form of agriculture that humans kept around them all the time, because they could tie a line to the raft and drag it up and down a river as they walked along it. The river supplied water and protein from fish, and they basically dragged a floating salad bar with them to eat with the fish.

Aquaponics works much better with leafy, green stuff. The nutrient level is very low, and fish waste is almost entirely nitrogen. It's hard to grow fruiting plants in aquaponic setups, because you have to add P & K, and the fish don't like to swim in fertilizer. The most succesful setups that I have seen that are growing anything besides lettuce will pull out the fish water, mix in more ferts, and then water without letting the runoff get back into the tank.